I’m not quite sure what it says about the people who read political blogs but my post about a sign at a tube station has been one of the most popular on this blog for some time!
I see it’s also fired off all sorts of possible explanations for the sign, of which the best seems to be the thread at http://budgie-uk.livejournal.com/750967.html
Lynne Featherstone 
Lynne – the truth is some of us are very sad, and started commuting on the Northern line in the 1970’s to get to school. We can remember that the Northern line used to have a grotty branch that ran from Moorgate to Finsbury Park. The Finsbury Park platforms were taken over by the Victoria line, and the rest of the branch was absorbed by the late BR’s Great Northern line when that was electrified. Whilst some (but clearly not all) of the signage has been updated in the intervening years, nothing much seems to have changed to the quality of the service.